Re: [PATCH v2] ALSA: hda/tegra: enable clock during probe

[Sameer Pujar <spujar@xxxxxxxxxx>]

On 1/30/2019 10:10 PM, Takashi Iwai wrote:
> On Wed, 30 Jan 2019 13:45:49 +0100,
> Jon Hunter wrote:
> > On 25/01/2019 11:06, Sameer Pujar wrote:
> > > If CONFIG_PM is disabled or runtime PM calls are forbidden, the clocks
> > > will not be ON. This could cause issue during probe, where hda init
> > > setup is done. This patch enables clocks unconditionally during probe.
> > >
> > > Along with above, follwoing changes are done.
> > >    * enable runtime PM before exiting from probe work. This helps to avoid
> > >      usage of pm_runtime_get_sync/pm_runtime_put() in probe work.
> > >    * hda_tegra_disable_clocks() is moved out of CONFIG_PM_SLEEP check.
> > >    * runtime PM callbacks moved out of CONFIG_PM check
> > >
> > > Signed-off-by: Sameer Pujar <spujar@xxxxxxxxxx>
> > > Reviewed-by: Ravindra Lokhande <rlokhande@xxxxxxxxxx>
> > > Reviewed-by: Jon Hunter <jonathanh@xxxxxxxxxx>
> > > ---
> > >   sound/pci/hda/hda_tegra.c | 26 +++++++++++++++++---------
> > >   1 file changed, 17 insertions(+), 9 deletions(-)
> > >
> > > diff --git a/sound/pci/hda/hda_tegra.c b/sound/pci/hda/hda_tegra.c
> > > index c8d18dc..ba6175f 100644
> > > --- a/sound/pci/hda/hda_tegra.c
> > > +++ b/sound/pci/hda/hda_tegra.c
> > > @@ -219,7 +219,6 @@ static int hda_tegra_enable_clocks(struct hda_tegra *data)
> > >   	return rc;
> > >   }
> > >   
> > > -#ifdef CONFIG_PM_SLEEP
> > >   static void hda_tegra_disable_clocks(struct hda_tegra *data)
> > >   {
> > >   	clk_disable_unprepare(data->hda2hdmi_clk);
> > > @@ -227,6 +226,7 @@ static void hda_tegra_disable_clocks(struct hda_tegra *data)
> > >   	clk_disable_unprepare(data->hda_clk);
> > >   }
> > >   
> > > +#ifdef CONFIG_PM_SLEEP
> > >   /*
> > >    * power management
> > >    */
> > > @@ -257,7 +257,6 @@ static int hda_tegra_resume(struct device *dev)
> > >   }
> > >   #endif /* CONFIG_PM_SLEEP */
> > >   
> > > -#ifdef CONFIG_PM
> > >   static int hda_tegra_runtime_suspend(struct device *dev)
> > >   {
> > >   	struct snd_card *card = dev_get_drvdata(dev);
> > > @@ -283,7 +282,7 @@ static int hda_tegra_runtime_resume(struct device *dev)
> > >   	int rc;
> > >   
> > >   	rc = hda_tegra_enable_clocks(hda);
> > > -	if (rc != 0)
> > > +	if (rc)
> > >   		return rc;
> > >   	if (chip && chip->running) {
> > >   		hda_tegra_init(hda);
> > > @@ -292,7 +291,6 @@ static int hda_tegra_runtime_resume(struct device *dev)
> > >   
> > >   	return 0;
> > >   }
> > > -#endif /* CONFIG_PM */
> > >   
> > >   static const struct dev_pm_ops hda_tegra_pm = {
> > >   	SET_SYSTEM_SLEEP_PM_OPS(hda_tegra_suspend, hda_tegra_resume)
> > > @@ -551,9 +549,9 @@ static int hda_tegra_probe(struct platform_device *pdev)
> > >   
> > >   	dev_set_drvdata(&pdev->dev, card);
> > >   
> > > -	pm_runtime_enable(hda->dev);
> > > -	if (!azx_has_pm_runtime(chip))
> > > -		pm_runtime_forbid(hda->dev);
> > > +	err = hda_tegra_enable_clocks(hda);
> > > +	if (err)
> > > +		goto out_free;
> > We also need to think about power-domains here. Enabling the clocks
> > might not be enough as the appropriate power-domain needs to be enabled.
> > For 64-bit Tegra runtime-pm will handle the power-domains (assuming they
> > are populated in device-tree). So I still think it is better we call
> > pm_runtime_get_sync() at some point rather than just replying on
> > enabling the clocks.
> If I understand correctly the code, the pm domain is already activated
> at calling driver's probe callback.

If there are no further concerns, can we consider this for approval?

Thanks,
Sameer.

> thanks,
>
> Takashi
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